Ladle for steel or pig iron and mass for the lining thereof

ABSTRACT

A novel ladle lining composition for use in steel, cast iron and pig iron ladles, particularly in those ladle lining areas especially subject to attack by slag, applied by a per se known slinger technique, comprising silica, alumina, and zirconia, preferably 60 to 90 weight percent silica, 3 to 30 weight percent zirconia and 5 to 10 weight percent alumina having a grain size distribution prior to application of 30 to 55 percent - 0.06 mm, 5 to 30 percent 0.06 to 0.12 mm, 10 to 30 percent 0.12 to 0.5 mm, 0 to 20 percent 0.5 to 2.0 mm and 0 to 20 percent + 2.0 mm.

United States Patent [1 1 Horn et al.

[ 1 Oct. 9, 1973 [73] Assignee: Martin & Pagenstecher GmbH,

Cologne-Mulheim, Germany [22] Filed: Aug. 20, 1971 [21] Appl. No.; 173,507

[30] Foreign Application Priority Data Aug. 26, 1970 Germany. P 20 42 793.9

[56] I References Cited UNITED STATES PATENTS 1,818,506 8/1931 Ross et al. 106/68 3,010,837 11/1961- Rice 106/68 3,389,989 6/1968 Finkl 266/43 X 3,416,938 12/1968 Alper et a1 106/57 3,427,390 2/1969 Renkey et 266/43 X 3,527,450 9/1970 Wishon et al 266/39 Primary Examiner-Gerald A. Dost Attorney-Ralph D. Dinklage et a1.

[5 7 ABSTRACT A novel ladle lining composition for use in steel, cast iron and pig iron ladles, particularly in those ladle lining areas especially subject to attack by slag, applied by a per se known slinger technique, comprising silica, alumina, and zirconia, preferably 60 to 90 weight percent silica, 3 to 30 weight percent zirconia and 5 to 10 weight percent alumina having a grain size distribution prior to application of 30 to 55 percent 0.06 mm, 5 to 30 percent 0.06 to 0.12 mm, 10 to 30 percent 0.12 to 0.5 mm, 0 to 20 percent 0.5 to 2.0 mm and O to 20 percent 2.0 mm.

9 Claims, 1 Drawing Figure LADLE FOR STEEL'OR PIG IRON AND MASS FOR THE LINING THEREOF This invention relates to a ladle for steel or pig iron having a lining which has been applied by slinging. The lining of such ladles is performed by the well-known technique of slinging plugs (bales) of the lining mass by the rotating head of aslinging machine in a quick sequence and with high velcocity into the free space between the ladle wall and an interior gage inserted in the ladle soas to confine the slung mass between it and the inside wall of the ladle. The mass is then dried and sintered, for example by means of metal melts therein. Slinger machines per se are well known, seefor instance Brit. Pat. No. 210.025.

The slung lining masses used in the trade generally comprise SiO, and A150 So for instance a well-known mass is composed of:

88.0 percent SiO 6.5 percent A1 1.1 percent ep 6.5 percent H 0.

Such slung refractory linings for steel, cast iron and pig iron ladles generally have a good durability. However,the refractory linings do not wear uniformly along the ladle height. The'greatest wear areas are observed in the zone of most serious slag aggression, i.e., in the upper region of the ladle, and about 50 to 100 cms above the ladle bottom. Such a wear profile occurs particularly markedlyfor instance in in ladles in which a vacuum and/or scavenging gas treatment is performed. Attempts have already been made to compensate for this increased aggression by the slag against the refractorylining'by providing a thicker lining in the said regions. The disadvantage of this type of action however is that the loading capacity of the ladle is reduced be cause the inside diameters thereof are effectively reduced in certain areas. It was also noted that the reinforced zones are subject to increased erosion by the metallic melt. The reinforcement of the refractory lining therefore has not been able to bring about the intended improvements.

It is known that refractory bricks having an increased resistance to attack by slag have already been used in the zones of greatest wear when lining ladles with refractory bricks. It is known to use high aluminaferous refractory bricks for this purpose.

ltiwould therefore appear to be obvious to increase the alumina content of the refractory ladle linings slung into place by the known technique related above in order to improve the resistance of the ladle lining to slag attack. This obvious technique for improving the durability and effectiveness of the ladle lining has not proven successful because it has been found as a'practical matter that such linings having increaseed alumina contents tend to severely shrink during heating causing cracks to appear in the lining. These cracks permit penetration'by the molten metal which back flushes the lining thus causing entire sections of it to break loose from the ladle.

The problem of providing ladles for steel or pig iron with a slung lining which has an increased'resistance against slag aggression without thickening portions of the lining has not as yet been solved.

lt is therefor an object of this invention to provide a novel solution to this problem.

Another object of this invention is to provide a novel or pig iron ladles.

" ladle lining for use in connection with steel, cast iron Other and additional objects of this invention will be- I come apparent from a consideration of this entire specification including the claims and the drawing hereof.

Understanding of this invention will be facilitated by reference to the accompanying drawing whose single FIGURE is an elevation partially in section of a ladle and ladle lining according to this invention.

In accord with and fulfilling the above objects, one aspect of this invention resides in utilizing a ladle lining composition comprising alumina, silica and zirconia.

The zirconia is advantageously introduced in the form of zircon sand. In doing so, the silica proportion of the zircon sand must be considered when determining the total silica content of the lining.

The subject of the invention therefore is a ladle for steel or cast iron, or pig iron with a. lining applied by slinging and containing SiO and A1 0 as essential constituents, which according to the invention comprises about 5 to 50 weight percent zircon sand in regions of heavy slag aggression. 5 to 20 percent zircon sand is preferred.

'This preferred range holds true in case an optimum compromise is to be utilized between-the cost and the technical effect. In the event one desires to care less for the cost factor (high cost of zirconium sand), the preferred content for zirconium sand also can be up to 30 percent of the mass.

A composition particularly suited for sligning the refractory lining of a ladle for steel or pig iron according to the invention is composed of:

60 90 percent SiO 3 30 percent ZrO 5 10 percent A1 0 I 1 including iron, titanium, alkalioxides and other conventional secondary materials.

The ladle lining masses preferably contain:

90 percent SiO 3 15 percent ZrO 5 10 percent A1 0 I including iron, titanium, alkali oxides and other conventional secondary materials.

According to theabove statements on the preferred range of zirconium sand, which possibly can also go up to 30 percent, here the preferred range is specifically extended in particular to higher ZrO contents. The content of the mass in ZrO according to this embodiment can also go to 20 percent instead of only to 15 percent. Then the preferred composition of the mass cloud be varied to the effect that it is:

70 percent SiO 5 20 percent ZrO 3 10 percent A1 0 remainder iron, titanium, alkali metal oxides and other usual accompanying materials. All quantity citations in percent by weight are related to the dry mass.

In the mentioned ladle lining masses according to the invention, low ZrO values should be associated to high SiO contents, and low SiO values should be associated to high ZrO- contents. The A1 0 content of the mass is advantageously selected such that all quartzes are completely enveloped and a sufficiently strong sinter layer of the lining is achieved when using the steel, cast iron and pig iron ladles. In order to prepare the masses according to the invention ready for application, 5 l2 of the ladle lining applied by the slinger technique can,

be obtained if the mass has the following grain structure:

The following grain structure is preferred:

A further aspect of this invention, which results in still further improvement, is the correlation of the SiO:, D0,, and A1 0 proportions as well as the grain sizing of the mass to the respective operational conditions such as slag and steel composition or slag and steel temperature.

In the drawing, a steel cast ladle according to the invention has a shell 1 consisting of steel sheet material a permanent liner 2 directly adjacent the shell 1, a bottom 3 of the ladle, and a refractory lining 4 applied by slinging. In the central, largestsection 4a of this lining 4, the lining constitutes a mass having a conventional composition of about 90 percent SiO,, 7 percent Al O plus the usual secondary materials and considering normal firing losses. In the zones denominated 4b and 4c in which the heaviest slag aggression occurs, the lining has a composition according to the invention in which a part of SiO, content has been replaced by zircon sand. For example, this mass 4a and 4c is composed of:

85 percent SiO:, 6 percent ZrO,, 6 percent A1 0 plus the usual secondary elements and considering the normal firing losses.

' By using the mass according to the invention, the life of the ladle in the zones 4b and 40 has been able to be increased by about percent.

What is claimed is:

l.-Ladle for use in connection with molten steel, cast iron or pig iron comprising a metal shell and a lining applied by slinging comprising silica and alumina which lining is modified in those regions of strong slag attack to consist essentially of at least 60 percent by weight silica, the balance consisting essentially of alumina and zirconia.

' 2. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 50 weight percent zirconium sand.

3. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 30 weight percent zirconium sand.

4. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 20 percent zirconium sand.

5. A ladle according to claim 1 whose modified lining comprises 60 90 percent SiO 3 30 percent ZrO 5 10 percent A1 0 remainder iron, titanium oxide, alkali oxides and other usual accompanying elements, based on dry mass.

6. A ladle according to claim 5, whose modified lining comprises 90 percent SiO,, 3 15 percent ZrO,, 5 10 percent A1 0 remainder iron, titanium oxide, alkali oxide and other usual accompanying elements, based on dry mass.

7. A ladle according to claim 5, whose modified lining comprises 70 to percent SiO,.,

5 to 20 percent ZrO 3 to 10 percent A1 0 remainder iron, titanium oxide,

alkali oxide and other usual accompanying elements, based on dry mass.

8. A ladle according to claim 5, whose modified lining is composed of particles having a grain structure of 30-55 0.06O mm ,5 30 %=0.060 to 0.12 mm, l0-30%=0.12 to 0.5 mm,O-20%=0.5 to 2.0 mm, andO-20%= 2.0 mm.

9. A ladle according to claim 5, whose modified lining is composed of particles having a grain structure of 40 50% 0.060 mm, 15 20 0.060 to 0.12 mm, l5 25 %=0.l2 toO.5 mm, 5 l5 %=0.5 to 2.0

mm and 5 15 20 mm.

" STATES PATENT OFFICE CORRECTlQN Yateht No; 9 I Dated October 9, 1973 03mm HORNQGERT 'K6NIG., J ACHIM KOENITZER, HANS}! J WOLFGANG LUDWIG v} I It is certified that; error appears' in the above-identified patcnt Qfhnd ibers-Q berr'r s 'Pa-rent aref. hereby corrected jag; shown below;

si idg na saied ihi's 27th da bf Augfijst 1974.

(S L) -it i i 'k I 'f '1M ;?coYIi-M I N; s MARSHAL'L DANN i Arresting Offi cler I I v Commission'erof Pat nt s a 

2. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 50 weight percent zirconium sand.
 3. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 30 weight percent zirconium sand.
 4. Ladle according to claim 1, wherein the modified lining was applied from a composition comprising about 5 to 20 percent zirconium sand.
 5. A ladle according to claim 1 whose modified lining comprises 60 - 90 percent SiO2, 3 - 30 percent ZrO2, 5 - 10 percent Al2O3, remainder iron, titanium oxide, alkali oxides and other usual accompanying elements, based on dry mass.
 6. A ladle according to claim 5, whose modified lining comprises 75 - 90 percent SiO2, 3 - 15 percent ZrO2, 5 - 10 percent Al2O3, remainder iron, titanium oxide, alkali oxide and other usual accompanyIng elements, based on dry mass.
 7. A ladle according to claim 5, whose modified lining comprises 70 to 85 percent SiO2, 5 to 20 percent ZrO2, 3 to 10 percent Al2O3 remainder iron, titanium oxide, alkali oxide and other usual accompanying elements, based on dry mass.
 8. A ladle according to claim 5, whose modified lining is composed of particles having a grain structure of 30 - 55 % <0.060 mm , 5 - 30 % 0.060 to 0.12 mm, 10 - 30 % 0.12 to 0.5 mm, 0 - 20 % 0.5 to 2.0 mm, and 0 - 20 % >2.0 mm.
 9. A ladle according to claim 5, whose modified lining is composed of particles having a grain structure of 40 - 50% <0.060 mm, 15 - 20 % 0.060 to 0.12 mm, 15 - 25 % 0.12 to 0.5 mm, 5 - 15 % 0.5 to 2.0 mm and 5 - 15 % >2.0 mm. 